Vehicles, such as two-wheeled vehicles (motorbikes) or four-wheeled vehicles, are equipped with a vehicle front lamp, such as a headlamp, for forward illumination of the road and such. Halogen bulb lamps, HID lamps, etc. are conventionally used as the light source in the vehicle front lamp.
Recent years have seen aggressive progress in the development of products in which semiconductor light-emitting elements such as light emitting diodes (LEDs) are used as light sources. LEDs are also being considered as a light source for vehicle front lamps due to their luminous efficiency, which exceeds that of HID lamps, as well as their long lifespan.
For example, a vehicle front lamp using LEDs that includes an LED module, a drive circuit that controls driving of the LED module, and a heat dissipating component that dissipates heat generated by the LED module has been proposed. Additionally, a vehicle front lamp using two LED modules that includes both low beam (passing beam) and high beam (driving beam) functions has also been proposed.
An LED itself generates heat as a result of emitting light, and this heat causes the temperature of the LED to increase and the light output of the LED to decrease. Moreover, an LED malfunctions at a relatively low 150 to 175 degrees Celsius. Additionally, when the intended use is in a vehicle, the temperature of the surrounding area in which the vehicle front lamp is used is a high 125 degrees Celsius, which translates into an allowed increase in temperature of only 25 to 50 degrees Celsius. As such, when LEDs are used as the light source in a vehicle front lamp, it is necessary to effectively dissipate the heat generated by the LEDs. Particularly when two LED modules are used, it is necessary to dissipate heat even more effectively.
Consequently, with conventional vehicle front lamps, provision of a large heat sink (heat dissipating component) is common, leading to an increase in the size and weight of the vehicle front lamp (front lamp ASSY) and thus an increase in cost.
In light of the above, vehicle front lamps that aim to favorably dissipate heat from the LED and the drive circuit have been proposed. For example, Japanese Unexamined Patent Application Publication No. 2013-030371 discloses a vehicle front lamp including a heat dissipating component (heat sink) having an extending portion that extends forward, an LED module for low beam use arranged on the top surface of the extending portion, an LED module for high beam use arranged on the bottom surface of the extending portion, a reflector that reflects light emitted from the two LED modules forward, and a drive circuit that controls driving of the two LED modules.
The vehicle front lamp disclosed in Japanese Unexamined Patent Application Publication No. 2013-030371, further includes a shade for forming the cut-off line for the low beam. The shade is attached to a leading end portion of the extending portion.
In another example, Japanese Unexamined Patent Application Publication No. 2007-207528 discloses a vehicle front lamp including first and second LED units, first and second reflectors, and a light source stand that supports the first and second LED units. In this vehicle front lamp, the first LED unit is fixed to the light source stand with a first clip, and the second LED unit is fixed to the light source stand with a second clip.